The following paragraphs are not an admission that anything discussed in them is prior art or part of the knowledge of persons skilled in the art.
U.S. Pat. No. 6,178,967 to Barnes, Sr. discloses a mouth protector designed to minimize discomfort and speech interference associated with conventional athletic mouthpieces and includes a pair of posterior splints for encompassing the posterior teeth. Each posterior splint includes an inner and outer wall, both of which terminate at or near the gum line so as to minimize discomfort to the wearer. The posterior splints may be interlinked with a connecting strip that is disposed behind the anterior teeth and extends across the wearer's palate. The device is designed to protect either the upper or lower posterior teeth while allowing a wearer's tongue to contact the anterior teeth thereby minimally interfering with clear speech.
United States Patent Publication No. 20080206707 to Gelb discloses oral appliances which reside within the mouth and which bring the lower jaw and/or the tongue forward to increase airway flow during sleep or physical activity. The oral appliances are constructed such that they may be optionally customized to an individual user's mouth shape. Methods of using such oral appliances are also provided.
United States Patent Publication No. 20090020130 to Eubank discloses an oral appliance that includes a first arch adapted to receive at least some of a user's teeth and a second arch adapted to receive at least some of the user's teeth. The first arch includes an anterior substantially planar region. The second arch includes an anterior bearing point that contacts the anterior substantially planar region of the first arch when the user bites down with the oral appliance inserted in the user's mouth and the user's temporomandibular joint in its proper natural position. The oral appliance may be used to help maintain stability of one or more aspects of the user's masticatory system, including at least helping to maintain proper positioning of the user's temporomandibular joint.